
//-----------------------------------------------------------------------------
// MurmurHash3 was written by Austin Appleby, and is placed in the public
// domain. The author hereby disclaims copyright to this source code.

// Note - The x86 and x64 versions do _not_ produce the same results, as the
// algorithms are optimized for their respective platforms. You can still
// compile and run any of them on any platform, but your performance with the
// non-native version will be less than optimal.

#include "murmur.h"

#define FORCE_INLINE inline __attribute__((always_inline))

FORCE_INLINE uint32_t rotl32 ( uint32_t x, int8_t r )
{
    return (x << r) | (x >> (32 - r));
}

FORCE_INLINE uint64_t rotl64 ( uint64_t x, int8_t r )
{
    return (x << r) | (x >> (64 - r));
}

#define ROTL32(x,y) rotl32(x,y)
#define ROTL64(x,y) rotl64(x,y)

#define BIG_CONSTANT(x) (x##LLU)

#define getblock(x, i) (x[i])

//-----------------------------------------------------------------------------
// Finalization mix - force all bits of a hash block to avalanche

FORCE_INLINE uint32_t fmix32(uint32_t h)
{
    h ^= h >> 16;
    h *= 0x85ebca6b;
    h ^= h >> 13;
    h *= 0xc2b2ae35;
    h ^= h >> 16;

    return h;
}

//----------

FORCE_INLINE uint64_t fmix64(uint64_t k)
{
    k ^= k >> 33;
    k *= BIG_CONSTANT(0xff51afd7ed558ccd);
    k ^= k >> 33;
    k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
    k ^= k >> 33;

    return k;
}

//-----------------------------------------------------------------------------

void MurmurHash3_x86_32(const void *key, int len, uint32_t seed, void *out )
{
    const uint8_t * data = (const uint8_t*)key;
    const int nblocks = len / 4;

    uint32_t h1 = seed;

    uint32_t c1 = 0xcc9e2d51;
    uint32_t c2 = 0x1b873593;

    int i;

    //----------
    // body

    const uint32_t * blocks = (const uint32_t *)(data + nblocks*4);

    for(i = -nblocks; i; i++) {
        uint32_t k1 = getblock(blocks,i);

        k1 *= c1;
        k1 = ROTL32(k1,15);
        k1 *= c2;

        h1 ^= k1;
        h1 = ROTL32(h1,13);
        h1 = h1*5+0xe6546b64;
    }

    //----------
    // tail

    const uint8_t * tail = (const uint8_t*)(data + nblocks*4);

    uint32_t k1 = 0;

    switch(len & 3) {
        case 3: k1 ^= tail[2] << 16;
        case 2: k1 ^= tail[1] << 8;
        case 1: k1 ^= tail[0];
                k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
    }

    //----------
    // finalization

    h1 ^= len;

    h1 = fmix32(h1);

    *(uint32_t*)out = h1;
}

//-----------------------------------------------------------------------------

void MurmurHash3_x86_128(const void *key, const int len, uint32_t seed,
        void *out)
{
    const uint8_t * data = (const uint8_t*)key;
    const int nblocks = len / 16;

    uint32_t h1 = seed;
    uint32_t h2 = seed;
    uint32_t h3 = seed;
    uint32_t h4 = seed;

    uint32_t c1 = 0x239b961b;
    uint32_t c2 = 0xab0e9789;
    uint32_t c3 = 0x38b34ae5;
    uint32_t c4 = 0xa1e38b93;

    int i;

    //----------
    // body

    const uint32_t * blocks = (const uint32_t *)(data + nblocks*16);

    for(i = -nblocks; i; i++) {
        uint32_t k1 = getblock(blocks,i*4+0);
        uint32_t k2 = getblock(blocks,i*4+1);
        uint32_t k3 = getblock(blocks,i*4+2);
        uint32_t k4 = getblock(blocks,i*4+3);

        k1 *= c1;
        k1  = ROTL32(k1,15);
        k1 *= c2;
        h1 ^= k1;

        h1 = ROTL32(h1,19);
        h1 += h2;
        h1 = h1*5+0x561ccd1b;

        k2 *= c2;
        k2  = ROTL32(k2,16);
        k2 *= c3;
        h2 ^= k2;

        h2 = ROTL32(h2,17);
        h2 += h3;
        h2 = h2*5+0x0bcaa747;

        k3 *= c3;
        k3  = ROTL32(k3,17);
        k3 *= c4;
        h3 ^= k3;

        h3 = ROTL32(h3,15);
        h3 += h4;
        h3 = h3*5+0x96cd1c35;

        k4 *= c4;
        k4  = ROTL32(k4,18);
        k4 *= c1;
        h4 ^= k4;

        h4 = ROTL32(h4,13);
        h4 += h1;
        h4 = h4*5+0x32ac3b17;
    }

    //----------
    // tail

    const uint8_t * tail = (const uint8_t*)(data + nblocks*16);

    uint32_t k1 = 0;
    uint32_t k2 = 0;
    uint32_t k3 = 0;
    uint32_t k4 = 0;

    switch(len & 15) {
        case 15: k4 ^= tail[14] << 16;
        case 14: k4 ^= tail[13] << 8;
        case 13: k4 ^= tail[12] << 0;
                 k4 *= c4;
                 k4  = ROTL32(k4,18);
                 k4 *= c1;
                 h4 ^= k4;

        case 12: k3 ^= tail[11] << 24;
        case 11: k3 ^= tail[10] << 16;
        case 10: k3 ^= tail[ 9] << 8;
        case  9: k3 ^= tail[ 8] << 0;
                 k3 *= c3;
                 k3  = ROTL32(k3,17);
                 k3 *= c4;
                 h3 ^= k3;

        case  8: k2 ^= tail[ 7] << 24;
        case  7: k2 ^= tail[ 6] << 16;
        case  6: k2 ^= tail[ 5] << 8;
        case  5: k2 ^= tail[ 4] << 0;
                 k2 *= c2;
                 k2  = ROTL32(k2,16);
                 k2 *= c3;
                 h2 ^= k2;

        case  4: k1 ^= tail[ 3] << 24;
        case  3: k1 ^= tail[ 2] << 16;
        case  2: k1 ^= tail[ 1] << 8;
        case  1: k1 ^= tail[ 0] << 0;
                 k1 *= c1;
                 k1  = ROTL32(k1,15);
                 k1 *= c2;
                 h1 ^= k1;
    }

    //----------
    // finalization

    h1 ^= len;
    h2 ^= len;
    h3 ^= len;
    h4 ^= len;

    h1 += h2;
    h1 += h3;
    h1 += h4;
    h2 += h1;
    h3 += h1;
    h4 += h1;

    h1 = fmix32(h1);
    h2 = fmix32(h2);
    h3 = fmix32(h3);
    h4 = fmix32(h4);

    h1 += h2;
    h1 += h3;
    h1 += h4;
    h2 += h1;
    h3 += h1;
    h4 += h1;

    ((uint32_t*)out)[0] = h1;
    ((uint32_t*)out)[1] = h2;
    ((uint32_t*)out)[2] = h3;
    ((uint32_t*)out)[3] = h4;
}

//-----------------------------------------------------------------------------

void MurmurHash3_x64_128(const void *key, const int len, const uint32_t seed,
       void *out)
{
    const uint8_t * data = (const uint8_t*)key;
    const int nblocks = len / 16;

    uint64_t h1 = seed;
    uint64_t h2 = seed;

    uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
    uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);

    int i;

    //----------
    // body

    const uint64_t * blocks = (const uint64_t *)(data);

    for(i = 0; i < nblocks; i++) {
        uint64_t k1 = getblock(blocks,i*2+0);
        uint64_t k2 = getblock(blocks,i*2+1);

        k1 *= c1;
        k1  = ROTL64(k1,31);
        k1 *= c2;
        h1 ^= k1;

        h1 = ROTL64(h1,27);
        h1 += h2;
        h1 = h1*5+0x52dce729;

        k2 *= c2;
        k2  = ROTL64(k2,33);
        k2 *= c1;
        h2 ^= k2;

        h2 = ROTL64(h2,31);
        h2 += h1;
        h2 = h2*5+0x38495ab5;
    }

    //----------
    // tail

    const uint8_t * tail = (const uint8_t*)(data + nblocks*16);

    uint64_t k1 = 0;
    uint64_t k2 = 0;

    switch(len & 15) {
        case 15: k2 ^= ((uint64_t)tail[14]) << 48;
        case 14: k2 ^= ((uint64_t)tail[13]) << 40;
        case 13: k2 ^= ((uint64_t)tail[12]) << 32;
        case 12: k2 ^= ((uint64_t)tail[11]) << 24;
        case 11: k2 ^= ((uint64_t)tail[10]) << 16;
        case 10: k2 ^= ((uint64_t)tail[ 9]) << 8;
        case  9: k2 ^= ((uint64_t)tail[ 8]) << 0;
                 k2 *= c2;
                 k2  = ROTL64(k2,33);
                 k2 *= c1;
                 h2 ^= k2;

        case  8: k1 ^= ((uint64_t)tail[ 7]) << 56;
        case  7: k1 ^= ((uint64_t)tail[ 6]) << 48;
        case  6: k1 ^= ((uint64_t)tail[ 5]) << 40;
        case  5: k1 ^= ((uint64_t)tail[ 4]) << 32;
        case  4: k1 ^= ((uint64_t)tail[ 3]) << 24;
        case  3: k1 ^= ((uint64_t)tail[ 2]) << 16;
        case  2: k1 ^= ((uint64_t)tail[ 1]) << 8;
        case  1: k1 ^= ((uint64_t)tail[ 0]) << 0;
                 k1 *= c1;
                 k1  = ROTL64(k1,31);
                 k1 *= c2;
                 h1 ^= k1;
    }

    //----------
    // finalization

    h1 ^= len;
    h2 ^= len;

    h1 += h2;
    h2 += h1;

    h1 = fmix64(h1);
    h2 = fmix64(h2);

    h1 += h2;
    h2 += h1;

    ((uint64_t*)out)[0] = h1;
    ((uint64_t*)out)[1] = h2;
}

//-----------------------------------------------------------------------------

